Electrical insulator



Sept. 15, 1931. A. NYMAN ELECTRICAL INSULATOR Filed May 1'7, 1924 3 Sheets-Sheet l INVENTOR ALEXANDER NYMAN ATTORNEY Sept. 15, 1931. NYMAN ELECTRICAL INSULATOR Filed Ma; 1 1924 3 Sheets-Sheet INVENTOR ALfXANDE/P NY/WA/V ATTORNEY A. NYMAN Sept. 15, 1931.

ELECTRICAL INSULATOR Filed May 17, 1924 3 Sheets-Sheet 5 INVENTOR ALfXAA/DEP NYMAN ATTORNEY Patented Sept.- 15, 1931 UNITED STATES PATENT OFFICE ALEXANDER NYMAN, OF EAST ORANGE, NEW JERSEY, ASSIGNOR 'I'O DUIBILIER CON- DENSER CORPORATION, A CORPORATION OF DELAWARE ELECTRICAL 'INSULATOR Application filed May 17, 1924. Serial No. 714,060.

. imparting a relatively large electrical capacity to each section, to prevent a comparatively great concentration of potential thereon.

A further object of the invention is to provide an insulator comprising sections each of which contains separate and distinct groups of sheets or the like of electrically conductive material separated by a dielectric, each group being a unit, and the various units constituting a condenser. The units are so disposed in each section that, when the section is mounted in operative position, the dielectric sheets and the sheets of conductingmate rial comprised in each unit will be maintained in the most efiicient relation, and the insulator thereby kept constantly in condition to operate to the best advantage.

. Further objects and advantages of the invention will 'be apparent from the following description, taken with the accompanying drawings in which one or more preferred embodiments of my invention are illustrated;

and the novel features are defined in the appended claims. But I, of course, reserve the right to make changes as to matters of size, shape and arrangement of various parts, without overstepping the limits of the nature and scope of the invention as herein set forth, to the full extent I indicated by the broad meanings of the terms in which the appended claims are expressed.

On the drawings, 1

Figure 1 shows diagrammatically the manner in which an insulator according to my invention is mounted in service;

- Figure 2 is a view partly in section and I partly in elevation, showing how the sections of the condenser are assembled when the insulator is to be suspended, with the sections depending one from another, upon an overhead support; and

Figure 3 is a view similar to Figure 2, showing another form of an insulator including sections to be piled or stacked up upon one another, the support being at the bottom.

Fig. 4 is a horizontal section taken through the casing of Figs. 2 and 3, and showing the radial arrangement of the condensers therein.

The same characters identify the same parts throughout.

Referring first to Figure 1, I show a number of insulators at I connected together in series, to form a so-called string hanging from an arm A of a post or column P; L being a conductor joined to the lowermost insulator. If the line voltage at the lower terminal of the insulator comprising the various sections C is say 100,000 volts, and there are ten such sections, each section should show a potential difference of 10,000 volts between its own particular terminals. Heretofore, however, such even distribution of voltage has not been obtained, because of capacit between the insulator as a whole and groun due to the proximity of the various sections I to the arm A and column P. This ground capacity has always been a serious factor and causes great expense, because the voltage between the terminals of the individual sections becomes progressively more from the arm A towards the line L and requires more sections I to take care of it. If the voltage between the terminals of the sections each should be about 10,000 volts, with ten sections in series, this potential difference may drop between the line L and arm A to such an extent that by the time the last or uppermost section I is reached, it may have a value of not more than five or six thousand 'volts, and unless the number of sections is increased, as a result the lower sections I are more liable to puncture or rupture because of the disproportionately large potentials to which they are subjected. The capacity existing between the string of sections I, and

thegi-ound, in Figure '1, is indicated in Figure 1 as if a number of separate condensers were connected from points between the va rious sections I to ground, as shown at g by the broken lines in Figure 1. In practice,'I have found that the drawback in question can be remedied without materially increasing the number of sections 1, largely by giving electrical capacity to the various sections I and makin this capacity large relatively to the groun capacity g of the various sections, and a practically uniform distribution of potential over the entire string of sections ofthe insulator is then obtained. For that purpose, I dispose in each section I a condenser of relatively large capacity, and make each section of my insulator as shown in Figures 2 and 3, the form in Figure 2 comprising a hollow casing or head 1, which has an open bottom and closed top and contains one or more individual condensers or units 2. The closed top of the head 1 has a perforated projection 3, and the open bottom is closed by the usual body 4 of porcelain or other nonconductive material of greater size or diameter than the head, designed to protect against creepage or flashing-overbetween the heads 1. Through the porcelain 4 of each section, extends an eyelet bolt 5 anchored fast on the inside of the head 1 and when a number of sections of this type are to be united to make an assembled insulator, the eyelet bolt 5, of

any one section, is secured to the perforated lug 3 of the section immediately below it.

Thus a string of sections can be made up and suspended from an overhead support such as the arm A in Figure 1.

Each of the condenser units 2, in the head 1, comprises sheets of insulation or dielectric 6 between which are metallic plates or sheets such as metal foil 7. The conductive elements 7 will all be in series in each unit, but the units themselves will be in parallel, as shown in Fig. 4, and there will be as man sheets 7 as are required for the potential di ference which is to be assigned to each section. Each unit 2 is clamped between a pressure block 8, the eifect of which can be ad] usted by means of a screw 9, at one end, and a wedge block 10 at the other, this wedge block being in the middle of the head 1.

'As shown in Figures 2 and14 the head of the section illustrated comprises six units 2, arranged around the inside of the head, one corresponding to each screw 9, the axis of each section extending outward radially from the central axis of the head 1; but the axis of each section 2 is not perpendicular to the central longitudinal axis of the head 1 or string, but is inclined with respect thereto in an outward and downward direction. Of course, the block 10 will have as many peripheral faces as there are sections 2, and this block will, therefore, have-a shape like that of a frustum of an inverted pyramid, and any two of its diametrically opposite The tendency of tension in the insulator of t, Fig. 2 or of compression in the insulator shown in Fig. 3, to, in either instance, comnated as an arch formation or as giving a toggle-joint action. The condenser will, therefore, always operate with high efliciency, becausecracks and other spaces between the mica and the sheets of foil cannot develop.

The block 10 has a threaded bore extending thereinto from the lower end to receive the threaded innerend of the eyelet bolt 5. The portion of this bolt which is enveloped by the insulating screen 4 has collars or flanges 12, which are milled to make them rough, and a central aperture or bore in the insulating shield 4 has inside corrugations, and is filled with cement 13, to hold the bolt 5 fast. The upper surface of the body 4 may be curved or spherical; while the lower surface is concave and provided with circular ribs 14 to increase the creepage distance from the center to the circumference. The head 1 may be filled with melted wax or sulphur to imbed the units 2 and the wedge block 10 therein.

..press the condenser elements, might be desig- With this form of section, a string of insulators can be assembled and each section will have sufliciently large capacity to make the ground capacity negligible, and distribute the voltage uniformly among the diflerent sections. At the same time, the weight of the sections, being exerted directly upon the wedge block 10 through the connecting eyelet bolts 5, will maintain the elements of each unit in most efficient engagement and secure the very best operation.

The modificationshown in Figure 3 embodies a section similar in all respects to that shownin Figure 2, except that the head 1 of each section has a boss 3a at the top in which is a threaded hole 312, and the sides or faces of the wedge block converge in an upward direction, and the longitudinal axes of the radially arranged units 2 are, therefore, inclined upward and outward. This section is intended for an insulator which is to be assembled by stacking or piling the sections one upon another, with a support at, thebottom instead of suspending it asin Figures 1 and 2, and the bolts 5a securing the sectionsv together, are threaded at both ends, so that signed for any voltage desired between the terminals of each section, and the units of each section being in parallel, the aggregate capacity of the condensers of each section can be made as large as desired. Of course, the heads 1, the blocks 8, wedge blockslO, and screws 5 or 5a are of some conductive material, so that while the units of each section are in parallel with one another, the combined units of each section are in series with the other sections. I

In both forms of insulators, each shield or body 4 is associated with a conden er of sufii cient capacity, the condensers being between the bodies 4 and being afiixed to the bodies 4 by the heads 1.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States ranged in the head, said units being inclined 1. An insulator comprising a hollow head having a closed top and open bottom, an insulator body closing the bottom of said head,

-a bolt passing through the insulator body,

condenser units each comprising conductive and dielectric elements radially arranged inside of said head and in inclined position, and a wedge block centrally located in said head and attached to said bolt so as to compress said condenser units by means of stress in said bolt.

2. An insulator comprising a hollow head, having a closed top and open bottom, an insulator body closing the bottom of said head, said body being of larger diameter than the head and being provided with corrugations to increase the surface thereof, condenser units; each comprising conductive and dielectric elements radially arranged inside of said head and inclined towards the top of the head, a bolt passing through said insulator body, and a wedge block attached to said bolt and centrally located in said head to compress said units by means of stress in said olt..

3. An insulator comprising a head with a closed top, an outside attachment means on' said top, an insulator bodyclosing the bottom of the head, conductive and dielectric elements forming condenser units radially aroutward and downward, a correspondingly shaped wedge block centrally disposed in the he'ad to engage the adj acent-ends of said units and compress same, and a tension means passing through said insulator into the block.

4;. An insulator adapted to form a unit in a series of insulators and to transmit mechanical stress comprising condenser units as compression members composed of alternate sheets of conductive and dielectric material, said units being arranged in arch formation to resist said stress. I

5. An insulator adapted to form a unit in a series of insulators and to transmit mechanical stress comprising condenser units as compression members composed of alternate sheets of conductive and dielectric material,-

said units being arranged at an obtuse angle with respect to each other at their inner ends, an element to support the outer ends ofthe units against spreading and means attached to their inner ends causing said mechanical stress to tend to cause the alignment of said units at said obtuse angle.

6. An insulator adapted jg resist a force, and including an electrical condenser, means to transmit said force to the body of the condenser to maintain a suitable pressure thereon, and an additional means to maintain pressure on the condenser.

7 A high tension insulator comprising an 7 insulator piece adapted to prevent flashover, means attached thereto for supporting a concondenser within one of said means for distributing the electrostatic stress along the ductor and the insulator, respectively, a stack vent fiashover, oppositely disposed means at- 1 tached thereto for supporting a conductor and the insulator, respectively, a plurality of stack condensers within one of said means for distributing the electrostatic stress along the insulator, means for adj'ustably exerting compression on said condenser stacks, and means for transmitting the mechanical strain on the insulator to exert further compression on the condenser stacks.

In testimony whereof I afix my signature.

ALEXANDER NYMAN. 

